Semiconductor forensic light kit

ABSTRACT

A semiconductor forensic light kit is disclosed. The forensic light kit may use a variety of semiconductor light sources to produce light that contrasts forensic evidence against its background for viewing, photographing and collection. Example semiconductor light sources for the forensic light kit include light emitting diodes and laser chips. A heat sink, thermoelectric cooler and fan may be included to keep the forensic light cool. Removable light source heads may be included on the forensic light kit to provide for head swapping to give the user access to different wavelengths of light.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation-in-part to U.S. patentapplication Ser. No. 10/360,327 filed on Feb. 7, 2003, now ______, and acontinuation-in-part to U.S. patent application Ser. No. 10/361,090filed on Feb. 7, 2003, now ______, both of which claim priority toclaimed to U.S. Provisional Patent Application Ser. No. 60/435,526 filedon Dec. 20, 2002, each of which is hereby incorporated by reference.This patent application is also a continuation-in-part to U.S. patentapplication Ser. No. 10/189,224 filed on Jul. 3, 2002, now ______, whichclaims priority to U.S. Provisional Patent Application Ser. No.60/304,324 filed on Jul. 10, 2001, and which is also acontinuation-in-part of U.S. patent application Ser. No. 10/016,992filed on Dec. 13, 2001, now ______, which is a continuation-in-part ofU.S. patent application Ser. No. 09/405,373 filed on Sep. 24, 1999, nowU.S. Pat. No. 6,331,111, each of which is hereby incorporated byreference.

BACKGROUND

In the field of forensic science, there is a need for a way to detectvarious evidence that may be used in a criminal prosecution, includingblood, saliva, other body fluids, hair, flesh, bone fragments, teeth,human skin damage such as bruises, bite marks or cuts, shoe prints,fingerprints, footprints, tire prints, gunpowder residue, bullets andportions thereof, explosive devices, explosive materials, parts ofexplosives, chemical weapons, chemical agents, biological weapons,paint, grease or oil, glass fragments, metal rubbings, fibers, dustpatterns, various trace evidence, alteration of documents (forgery,different inks), narcotics, herbal evidence, and components, residuesand traces thereof.

In the past, forensic personnel used high intensity conventional lightsources, such as halogen bulbs, or ion gas laser light sources in orderto illuminate areas of a crime scene and attempt to detect evidencesince some evidence such as fingerprints do not fluorescence brightlyalone. Contrast between such evidence being sought and the backgroundagainst which it was found was sometimes achieved by using fluorescentdusting powder, dye, or other marker material, and light having awavelength that substantially coincides with a known excitationwavelength of the marker. The characteristic of the marker is that, uponillumination with light at one of its excitation wavelengths, it willfluoresce, or emit light. Such fluorescence is typically at a longerwavelength as compared to the excitation wavelength. Examination ofevidence was also enhanced through the use of color filtering glasses orbarrier filters, whose color filtering characteristics are tuned tomaximize the image to be detected. The forensic lights in the past hadnumerous drawbacks including bulky size, need for access to an AC powersupply, and high cost.

SUMMARY

Various structures and components of a forensic light that uses asemiconductor light sources are disclosed.

DETAILED DESCRIPTION

Referring to FIG. 1, an example forensic light 100 is depicted. Itincludes a housing 101 that houses various components of the forensiclight, such as control circuitry and the battery pack. On the top of thehousing 101, there is a power level selection button 103 for selectingfull power in different level, and display lights (such as LED indicatorlights) for indicating power level of light operation. Different powerlevel operations may be needed for different detection purposes.Optionally, a tripod mounting attachment mechanism for camera use may beincluded. On the bottom of the housing there is a trigger 102 forinitiating and terminating light output from the forensic light. Sincethe forensic light produces light of an intensity that can damage thehuman eye, a spring loaded trigger may be provided so that if a user isnot actively soliciting light output by squeezing the trigger, output oflight from the forensic light will cease. A battery pack or a power pack105 may be included at the proximal end of the housing or main lightbody. The light can be operated by battery if the battery pack is usedand the light can be operated by AC power using a switching power supplyor by use of an automobile DC adaptor when a power pack is used. A lighthead 106 may be provided at the distal end of the housing or main lightbody that may be removable from the housing 101 or main body of theforensic light. The light head 106 may contain the light source andother components. Since the light source produces heat as well as light,it may be desirable to include ventilation apertures 108 that permit airto enter the light head to provide a cooling effect. Additionally, airexit vents 107 are provided for air circulation through the light head.Light beams will exit the light head at the exit aperture 109 which mayinclude a protective cover to prevent dirt or moisture from damaging thelight source and which may also protect the light source from mechanicaldamage. In the light head, an adapter 111 may be included to permitviewing of forensic evidence through filters, focusing lenses, diffusersand polarizers.

Referring to FIG. 2 a, if it is desired to have a battery-operatedforensic light, then a battery charger 201 may be provided. The batterycharger may include a body 202 with a periphery on which a receptacle203 may be provided for receiving electrical power. A battery receptacle204 may be provided for receiving batteries or a power pack forcharging. The battery used in the light operation is embedded in abattery pack. The battery charger can be operated by a AC power or anautomobile DC adapter power supply.

Referring to FIG. 2 b, an example battery pack or power pack 210 isdepicted. The battery pack 210 may include a plastic casing 205, a base205, a lock 208 and an electrical contact 208.

Referring to FIG. 3, a power pack unit 301 may be provided for operatingthe forensic light. The power pack 301 includes an AC power supply andplug 302 to receive AC power and convert it to DC power, a cable or wire303 to conduct electrical power, and a plug 304 to connect the cable tothe power pack 305. There is an electrical connection 306 for the powerpack to contact electronic circuitry within the forensic light. Thephysical configuration of the power pack 305 is the same as battery packso that the light unit can be operated by either battery pack or ACpower using a power pack.

Referring to FIG. 4, a provision has been made to operate the forensiclight by use of a DC adapter. This allows for convenient use of theforensic light in an automobile. The DC adaptor 401 has a DC plug 402 tofit into universal DC outlet such as found in an automobile, a cable orwire 403 to conduct power, and a plug 404 to connect the DC adapter to apower pack such as that depicted in FIG. 3.

By assembling a kit of the foregoing components, a forensic light kitmay be provided that is powered by a battery pack, AC power or DC power,at the user's discretion. Such a kit may include other components suchas the light heads of different wavelengths disclosed below and otherdesired hardware such as filters, glasses, etc.

Referring to FIG. 5, a cross sectional view of the forensic light 100 ofFIG. 1 is depicted. Control circuitry 501 is provided for controllingoperation of the light. The control circuitry controls the on/offfunction of the forensic light as well as light intensity. Electricalconnections 502 are provided for establishing electrical contact betweenthe main light body and the removable light head. The control circuitryis also connected to the power supply (either battery pack or power packas described above) through connection 503. A fan 504 may be providedwithin the light head for air circulation and heat dissipation.Individual semiconductor light producing devices 505 such as lightemitting diode (LED) modules (including LED chip mounted on a primaryheat sink and covered by a cover or plastic dome) or laser chips aremounted on the distal side of a thermoelectric (“TE”) cooler 507 whichis affixed to a secondary heat sink 508 that dissipates most of the heatproduced by the light producing devices. The semiconductor lightproducing devices may be mounted to a heat sink by heat conductiveadhesive 509. The TE cooler is optional and may be used in someapplications. The proximal side of the secondary heat sink 508 has afinned or comb-shaped wings to increase the surface area of thesecondary heat sink in order to increase contact of the heat sink withair and improve heat dissipation. Air from the fan moves past thesecondary heat sink for heat dissipation. A light reflector 510 such asa conical or parabolic reflector may be provided to collect light fromthe semiconductor light producing devices and direct it through a lightexit aperture 109 and/or cover or focus lens to produce useful lightbeams 511. An optional protective cover or focus lens 512 may beincluded at the light exit to protect electronic components from dirtand physical damage. If a focus lens is used, it can be used toconcentrate the light beam and determine a desired light footprint. Thenumber of semiconductor light producing devices can vary from 1 to anydesired number based on the power levels desired in the forensic light.

FIG. 6 depicts a side view of an LED module 600 according to a flip-chipdesign that can serve as a light source for a forensic light. The lightsource 600 includes a cover or dome 601 that serves to protect theLED(s) within from contamination from moisture and dirt and frommechanical damage. The dome 601 may also serve to focus light emitted bythe LED. A light emitting diode chip array 607 is mounted in invertedposition in a well 606 of a heat sink 605 according to the so-called‘flip chip’ design. In this example, the chip has an insulativesubstrate. The chip 607 is mounted on a flip chip pad 608 within thewell 606. Electrode beads or bumps 607 a and 607 b separate the chipfrom the pad but attach the chip to the pad and provide electricalconnection. The pad is affixed to the bottom of the well by a methodsuch as soldering, brazing, welding or use of a heat-conductive adhesive605. The chip has an electrode on top and its epitaxial layers(semiconductor material) facing down toward the pad and the bottom ofthe well in the figure. The pad upper surface may be light reflective sothat light is reflected from the pad in a useful direction. The pad maybe coated with a light reflective film, such as Au, Al or Ag. The heatsink may be surrounded by an insulative jacket 603. The chip is poweredvia wires 609 a and 609 b attached to intermediate islands 604 a and 604b which are in turn contacted by wires 602 a and 602 b. Light from thelight source is emitted as a beam 610 having an angle of departure θthat is defined and determined in part by the angle of the walls of thewell as well as by any focusing or restrictive characteristics of thedome. In such a package, all of the light emitted from the chip can bereflected back in the light exit direction for highest light output. Thewell may also include a reflective coating or polished surface.

FIG. 7 depicts an LED module 700 that includes a well 706 within a heatsink 705 and having a plurality or array of LED chips 707 a, 707 b, 707c, etc. within the well. The depth of the well can be from 0 mm to morethan 50 mm. Each individual LED chip may include semiconductor materialor epitaxial layers 709 a on a substrate 709 b. Each chip may be mountedto the heat sink by use of heat conductive adhesive or other mountingmeans. The chips in this figure are wired in series, although wiring inparallel is also possible when the application requires it. Theremainder of the features of the LED 700 module are similar to thosealready discussed.

FIG. 8 depicts a semiconductor light emitting module 800 that has asingle LED or laser chip 807 mounted in a well 806 of a heat sink 805.The chip 807 has a conductive substrate and may be mounted to the floorof the well of the heat sink by use of a heat conductive adhesive. Thedepth of the well can be from 0 mm to more than 50 mm. The chip ispowered by wire 809 from island 803. A wire lead 802 a brings electricalpower to the module. An insulative jacket 804 may be placed around theheat sink for electrical insulation. A negative electrode 802 isprovided on the bottom of the heat sink for electrical conduction.

FIG. 9 depicts an LED module 900 that includes an array of semiconductorlight producing chips 907 a, 907 b, etc. within a well of a heat sink.The chips use an electrically conductive substrate and there is anegative electrode 901 on the heat sink for electrical connection.

For forensic light sources with multiple semiconductor light producingchips, the quantity of chips used may vary depending on application, andcan range from 1 to several hundred. The spacing between chips can beadjusted from zero to more than 1 mm, depending on the applicationrequirements. The semiconductor chip producing light may be a singlechip or single chip array. The chip or chips may be mounted in a well ofa heat sink or may be mounted directly on a heat sink. The wavelength oflight emitted from each chip in a multi-chip forensic light design maybe the same wavelength or different wavelengths to cover a desired lightspectral range. If a well is provided in the heat sink, the depth of thewell may be as desired, such as from 0 to 50 mm or more, depending onapplication.

The forensic light source may be constructed with the chip(s) mounted tothe primary heat sink, such as by use of a heat conductive and/or lightreflective adhesive. The primary heat sink can be attached to asecondary heat sink if desired, such as by use of a heat conductiveand/or electrically insulative adhesive, welding, brazing, soldering ormechanical fixation.

The chip(s) may be any of those described herein or otherwise, such as aflip chip design. The primary heat sink, chip(s) and dome can becombined as a light module. A cover may be provided over the dome. Anexample cover would include a plastic fitting or attachment and a glasswindow through which light may travel. Glass generally has better lighttransmission qualities than plastic, but either could be used. The domecan serve as a focusing lens.

A reflective cone may be included in the forensic light, such as betweenthe dome and the light exit or apeture from which light exits theforensic light. The cone can be used for a light conservation purpose,to capture and use light that would be errant and would otherwise bewasted. The cone can also be used for the purpose of beam shaping and tocreate a light beam with a desired footprint. Example light beamfootprints include circular, oval, square, rectangular, and any othergeometric shape, depending on application. The footprint can be anydesired size for the application. A shaped beam can have superior lightintensity. The reflective cone can have an interior surface thatreflects light. Some cones may reflect at least as much as 85% of thelight that encounters them. Materials of cones can be plastic or metal,polished or plated metal such as aluminum or alloy, or otherwise. Use ofa cone allows superior maintenance of light beam intensity as distancefrom the chip(s) increases.

Heat sinks are often a combination of two different kinds of materials,the first with a low thermal expansion rate and the second with highthermal conductivity. Monolithic heat sinks may be used as well.Examples of some heat sink materials which may be used in lightsdepicted herein include metals, copper, aluminum, silver, magnesium,steel, silicon carbide, boron nitride, tungsten, molybdenum, cobalt,chrome, Si, SiO₂, SiC, AlSi, AlSiC, natural diamond, monocrystallinediamond, polycrystalline diamond, polycrystalline diamond compacts,diamond deposited through chemical vapor deposition and diamonddeposited through physical vapor deposition, and composite materials orcompounds. Any materials with adequate heat conductance and/ordissipation properties can be used. If desired, a heat sink may havefins or other surface modifications or structures to increase surfacearea or promote air flow and enhance heat dissipation.

Examples of heat conductive and/or electrically insulative adhesivesthat may be used are silver based epoxy, other epoxies, and otheradhesives with a heat conductive quality and/or electrically insulativequality. In order to perform a heat conductive function, it is importantthat the adhesive possess the following characteristics: (i) strongbonding between the materials being bonded, (ii) adequate heatconductance, (iii) electrically insulative or electrically conductive ifdesired (or both), and (iv) light reflectivity if desired, or anycombination of the above. Examples of light reflective adhesives whichmay be used to affix chips to a heat sink include silver and aluminumbased epoxy. One example heat conductive and electrically insulativeadhesive includes a mixture of a primer and an activator. In thisexample, the primer may contain one or more heat conductive agents suchas aluminum oxide (about 20-60%) and/or aluminum hydroxide (about15-50%). The primer may also contain one or more bonding agents such aspolyurethane methacrylate (about 8-15%), and/or hydroxyalkylmethacrylate (about 8-15%). An activator may be mixed with the primer toform an adhesive. The activator may include any desired catalyst, forexample n-heptane (about 5-50%), aldheyde-aniline condensate (about30-35%), isopropyl alcohol (about 15-20%), and an organocopper compound(about 0.01 to 0.1%). Adhesives such as described herein can be used tomount a chip to a primary heat sink, or to mount a primary heat sink toa secondary heat sink, or both.

Examples of substrates on which the semiconductors used in the forensiclights depicted herein may be grown include Si, GaAs, GaN, ZnS, ZnSe,InP, Al₂O₃, SiC, GaSb, InAs and others. Both electrically insulative andelectrically conductive substrates may be used.

Epitaxial layers and structures of semiconductor light emitting chipsuseful in forensic lights disclosed herein may include a substrate (suchas sapphire) that serves as a carrier pad or platform on which to growthe chip's epitaxial layers. The first layer placed on the substrate maybe a buffer layer (such as a GaN buffer layer). Use of a buffer layerreduces defects in the chip that would otherwise arise due todifferences in material properties between the epitaxial layers and thesubstrate. Then a contact layer, such as n-GaN, may be provided. Acladding layer such as n-AlGaN Sub may be present to confine injectedelectrons. An active layer may be provided to emit the light whenexcited by electrons. An example active layer is such as InGaN withmultiple quantum wells. The active layer is where electrons jump from aconduction band to valance and emit energy which converts to light. Onthe active layer, another cladding layer may be provided, such asp-AlGaN, to serve to confine electrons. A contact layer such as p+ GaNmay be provided that is doped for Ohmic contact. The contact layer mayhave an electrode mounted on it.

The physical dimension of the chip(s), including their surface area,used in the forensic light can impact the intensity of the lightproduced. The chips could be of any desired size and shape, and mightrange from a surface area of more than about 300 um. Each individualchip may have a power output more than about 20 mW. The chips may emitlight of any desired wavelength, including light from wavelengthsranging from 200 to 1500 nm.

Some examples of semiconductor light sources which may be desired to beused in a forensic light include light emitting diode chips, LED chiparrays (an LED chip with a large surface area and having paths ofelectrically conductive material projecting across some portions of itssurface to power the chip), laser diodes, vertical cavity surfaceemitting laser, edge emitting lasers, surface emitting lasers, andothers.

Example material which may be used in the TE cooler include includeBi₂Te₃, PbTe, SiGe, BeO₂, BiTeSe, BiTeSb, AlO₃, AlN, BaN and others.

Heat sinks used in the lights can be of a variety of shapes anddimensions, such as those depicted in the drawings or any others whichare useful for the structure of the particular light source beingconstructed. It should be noted that the heat sink arrangement should besufficient to prevent overheating of the semiconductor light source, ordiminished light production and shortened product life may result.

A user of the forensic light will find it advantageous to select a lightoutput frequency centered around a wavelength that tends to contrast theevidence being searched for against its background material. A table isprovided below suggesting some wavelengths that may be desired fordetecting various substances. Quick detachable light sources or headsfor the forensic light may be manufactured that produce each of thesespecific wavelengths so that the forensic light user has a kit availablewith an array of different light sources available.

Correlation of Light Wavelength to Substance Searched for

Color Substance UV (<400 nm) Fingerprints Near UV (405 nm) human skindamage such as bruises, bite marks or cuts Blue (450 nm) blood, saliva,other body fluids, hair, flesh, bone fragments Green (525 nm) shoeprints, fingerprints, footprints, tire prints, paint, grease or oil,glass fragments, metal rubbings, fibers, dust patterns, various traceevidence Yellow (590 nm) gunpowder residue, bullets, explosive materialsRed (630 nm) alteration of documents (forgery), narcotics, herbalevidence Infrared (>800 nm) Document examination

As desired, the forensic light may be configured to produce light thatcenters around a single wavelength, or multiple removable light sourcescapable of producing light of different wavelengths may be produced sothat the user may select a light source of the appropriate wavelengthfor his application. In addition, if desired the forensic the light maybe structured so that the user may select a light output power levelthat is less than full power output. For example, the forensic light maybe structured so that the user may select a light output power level of¼, ½, 3/4 or full light output power. An example of light power outputin milliwatts (mW) at those example levels for light centered on five(5) different wavelengths is shown in the table below.

Light Output Specifications (mW)

Color ¼ power ½ power ¾ power Full power UV (405 nm) 100 200 300 400Blue (450 nm) 250 500 750 1000  Green (525 nm) 200 400 600 800 Yellow(590 nm) 100 200 300 400 Red (630 nm) 100 200 300 400It is possible for the forensic light to output light at any of avariety of different wavelengths, including but not limited to 280 nm,350 nm, 400 nm, 405 nm, 450 nm, 525 nm, 590 nm, 630 nm, 800 nm, 980 nm,1064 nm, 1300 nm and 1500 nm. Power output levels could be from lessthan 1 mW to more than 9000 mW.

The advantage of being able to produce light at less than the full lightoutput power level is to provide contract against evidence background indifferent environment. It is also possible to produce forensic lightsthat have a fixed intensity power output. The forensic light may be usedto fluoresce or illuminate evidence, to contrast it with a background,to fluoresce or illuminate the background to contrast it with evidence,or to otherwise use light in detecting the presence of evidence.

Some other advantageous features that the forensic light may include arediscussed here. Portability is one such feature. The forensic light maybe configured as a hand-held, battery-operated device that may be usedat remote locations and may be easily transported and easily stored. Theforensic light may be adaptable to other equipment such as a camera orimage intensifying devices. The forensic light may be configured as aring light that attaches to the font end of a camera lens and or imageintensifying device thereby providing even illuminations of the desiredfield. In such a configuration the ring light could be constructed toaccept filters, allowing the device to be removed from the equipment andused to view evidence directly in the same manner that a handheldmagnifying glass would be used. Additionally, the forensic light may beconfigured to accept filters that positioned at the light output pointintended to manipulate the output. Such filters could be a diffuser tosoften or defocus the light being emitted, a focus lens to narrow thelight beam intensifying the light over a small area, narrowband pass fornarrowing the wavelength band being emitted, and or polarizing filter toplane polarize the light being emitted. Such filters and lenses arereadily and commercially available in a variety of sizes and shapes fromseveral sources. Such a configuration would also allow the attachment ofviewing filters and lenses for the user. The forensic light could beconfigured to accept both light output filters and lenses and viewingfilters and lenses simultaneously. Another optional feature is a cameramount that allows the forensic light to be positioned with respect to acamera in order to photograph forensic evidence. Forensic lights mayalso used to provide light in the non-visible spectra (such as the UVand IR ranges) that reflects off the evidence and may be detected by aphoton multiplier that in turn projects the light and image onto a viewscreen.

A forensic light constructed according to principles disclosed hereinmay be used to carry out a method for locating or detecting forensicevidence. Such a method may be designed or intended to locate varioustypes of forensic evidence or materials that may later be used in acriminal prosecution, civil proceedings, or for other purposes. Examplesof forensic evidence that a user of the forensic light may desire togather include but are not limited to blood, saliva, other body fluids,hair, flesh, bone fragments, teeth, human skin damage such as bruises,bite marks or cuts, shoe prints, fingerprints, footprints, tire prints,gunpowder residue, bullets and portions thereof, explosive devices,explosive materials, parts of explosives, chemical weapons, chemicalagents, biological weapons, paint, grease or oil, glass fragments, metalrubbings, fibers, dust patterns, various trace evidence, alteration ofdocuments (forgery, different inks), narcotics, herbal evidence, andcomponents, residues and traces thereof.

The method can include the steps of:

determining a type or class of forensic evidence sought to bediscovered,

determining or selecting the wavelength of light that may be useful indetecting such forensic evidence, such as by contrasting such forensicevidence against its background,

obtaining, setting, building or modifying a semiconductor forensic lightthat outputs light of such wavelength,

illuminating a physical area with the light output by the forensic lightin order to detect desired forensic evidence,

viewing any detected forensic evidence (viewing may take place through afilter, image intensifier if desired),

photograph the detected forensic evidence,

enhance or project any image of the evidence,

collect the detected forensic evidence, and

store the collected forensic evidence.

These method steps may be modified, steps may be omitted, or other stepsmay be added.

While the present lights have been described and illustrated inconjunction with a number of specific configurations, those skilled inthe art will appreciate that variations and modifications may be madewithout departing from the principles herein illustrated, described, andclaimed. The present invention, as defined by the appended claims, maybe embodied in other specific forms without departing from its spirit oressential characteristics. The configurations of lights described hereinare to be considered in all respects as only illustrative, and notrestrictive. All changes that come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

1. A semiconductor forensic light kit comprising: a battery charger,said battery charger being capable of charging a battery pack, an ACwall outlet cord for providing power to said battery charger, a DC poweradapter and cord, a semiconductor forensic light that includes a housinghaving a proximal end, a distal end, a top, a bottom and an interior,control circuitry located in said housing interior, said controlcircuitry being able to control on/off and power intensity selectionfunctions of the forensic light, an on/off button located on the top ofsaid housing, said on/off button being in operable connection with saidcontrol circuitry, a power level selection button located on the top ofsaid housing, said power level selection button accommodating theincrease and decrease of light output levels from the forensic light,said power level selection button being in operable communication withsaid control circuitry, a trigger said housing, said trigger serving toaccommodate initiation and terminate of light emission from the forensiclight, said trigger being in operable communication with said controlcircuitry, a power pack located at said housing proximal end forproviding electrical power to the forensic light, a plurality of lightheads located at said housing distal end, each of said light headsemitting light centered on a different wavelength than each of saidother heads, a light source within one of said light heads, said lightsource including a semiconductor light emitting device that can emitlight of a wavelength useful in detecting forensic evidence, a primaryheat sink to which said semiconductor light emitting device is affixed,said primary heat sink serving to draw heat away from said semiconductorlight emitting device, a secondary heat sink to which said primary heatsink is affixed, said secondary heat sink serving to dissipate heatproduced by said semiconductor light emitting device, a thermoelectriccooler located on said secondary heat sink, said thermoelectric coolerexperiencing a drop in temperature when subjected to a voltage, and afan serving to move air past said thermoelectric cooler in order to coolthe light source, at least one ventilation aperture on said light headfor permitting air to enter and exit the light head to facilitating heatdissipation, and at least one light exit on said light head, said lightexit being sized and shaped to permit light to exit said light head foruse in detecting forensic evidence.
 2. A forensic light kit as recitedin claim 1 wherein said light heads are detachable from said housingdistal end.
 3. A forensic light kit as recited in claim 1 wherein atleast one of said light heads emits light of a wavelength centered about450 nm.
 4. A forensic light kit as recited in claim 1 wherein saidsemiconductor light producing device is an LED module that include theprimary heat sink, an LED chip located in a well on the primary heatsink, and a dome over said LED chip, the LED chip including a substrateand epitaxial layers.
 5. A forensic light kit as recited in claim 1further comprising: a well in said primary heat sink, and a plurality ofsemiconductor light producing devices located in said well.
 6. Aforensic light kit as recited in claim 1 wherein at least one of saidheat sinks includes a material selected from the group consisting ofcopper, aluminum, silver, magnesium, steel, silicon carbide, boronnitride, tungsten, molybdenum, cobalt, chrome, Si, SiO₂, SiC, AlSi,AlSiC, and diamond.
 7. A forensic light kit as recited in claim 1wherein said semiconductor light producing device includes epitaxiallayers located on a substrate and wherein said substrate is selectedfrom the group consisting of Si, GaAs, GaN, ZnS, ZnSe, InP, Al₂O₃, SiC,GaSb, and InAs.
 8. A forensic light kit as recited in claim 1 whereinsaid semiconductor light producing device includes epitaxial layerslocated on a substrate, and at least one of the epitaxial layers isselected from the group consisting of: a buffer layer to reduce defectsin the chip that may arise due to differences in material propertiesbetween the epitaxial layers and the substrate, a contact layer, acladding layer serving to confine injected electrons, and an activelayer that emits the light when excited by electrons, the light emittedbeing useful in forensic detection of evidence.
 9. A forensic light kitas recited in claim 1 wherein said thermoelectric cooler includes amaterial selected from the group consisting of Bi₂Te₃, PbTe, SiGe, BeO₂,BiTeSe, BiTeSb, AlO₃, AlN, and BaN.
 10. A forensic light kit as recitedin claim 1 wherein said light head is capable of emitting light that isselected from the group consisting of blue, green, yellow, red, infraredand ultraviolet.
 11. A forensic light kit as recited in claim 1 whereinlight emitted by the forensic light is useful in detecting forensicevidence selected from the group consisting of blood, saliva, other bodyfluids, hair, flesh, bone fragments, teeth, human skin damage such asbruises, bite marks, cuts, shoe prints, fingerprints, footprints, tireprints, gunpowder residue, bullets and portions thereof, paint, grease,oil, glass fragments, metal rubbings, fibers, dust patterns, alterationof documents, narcotics, and herbal evidence.
 12. A semiconductorforensic light kit comprising: a battery charger, a battery chargercord, a semiconductor forensic light that includes a housing having aproximal end, a distal end, a top, a bottom and an interior, a pluralityof light heads located at said housing distal end, each of said lightheads emitting light centered on a different wavelength than each ofsaid other heads, each of said light heads being installable at saidhousing distal end, said light heads being quick detachable from saidhousing in order to accommodate removal of one light head andreplacement of it with another light head by a forensic technicianworking in the field, a light source within said light head, said lightsource including a semiconductor light emitting device that can emitlight of a wavelength useful in detecting forensic evidence, a primaryheat sink to which said semiconductor light emitting device is affixed,said primary heat sink serving to draw heat away from said semiconductorlight emitting device, and at least one light exit on said light head,said light exit being sized and shaped to permit light to exit saidlight head for use in detecting forensic evidence.
 13. A forensic lightkit as recited in claim 12 wherein said semiconductor light producingdevice is an LED module that include the primary heat sink, an LED chiplocated in a well on the primary heat sink, and a dome over said LEDchip, the LED chip including a substrate and epitaxial layers.
 14. Aforensic light kit as recited in claim 12 wherein said heat sinkincludes a material selected from the group consisting of copper,aluminum, silver, magnesium, steel, silicon carbide, boron nitride,tungsten, molybdenum, cobalt, chrome, Si, SiO₂, SiC, AlSi, AlSiC, anddiamond.
 15. A forensic light kit as recited in claim 12 wherein saidsemiconductor light producing device includes epitaxial layers locatedon a substrate and wherein said substrate is selected from the groupconsisting of Si, GaAs, GaN, ZnS, ZnSe, InP, Al₂O₃, SiC, GaSb, and InAs.16. A semiconductor forensic light kit comprising: a power cord, aforensic light that includes a handle, a plurality of light headslocatable at said housing distal end, at least one of said light headsemitting light centered on a different wavelength than at least one ofsaid other heads, at least one of said light heads being attachable toand removable from said housing, a light source within said light head,said light source including a semiconductor light emitting device thatcan emit light of a wavelength useful in detecting forensic evidence, aprimary heat sink to which said semiconductor light emitting device isaffixed, said primary heat sink serving to draw heat away from saidsemiconductor light emitting device, and at least one light exit on saidlight head, said light exit being sized and shaped to permit light toexit said light head for use in detecting forensic evidence.